List Manipulation

[Gerard Flanagan]

Roman wrote:
> Dennis Lee Bieber wrote:
> > On 4 Jul 2006 07:01:55 -0700, "Roman" <rgelfand2 at hotmail.com> declaimed
> > the following in comp.lang.python:
> >
> > > I would appreciate it if somebody could tell me where I went wrong in
> > > the following snipet:
> > >
> > 	It would help if you gave a sample of the input data (three lines
> > worth, say) AND an example of what the final output should be from those
> > three lines.
> >
> > >     for col in line:
> > >        p[:0].append(str(col))
> >
> > 	As has been pointed out, as soon as you used the [:0], you created a
> > local/temporary EMPTY slice of the original P, and you are appending one
> > column's value to this temporary, which is then thrown away.
> > import csv
> >
> > -=-=-=-=-=-=-=-		PROGRAM
> > p = []
> >
> > fin = open("firearms.csv", "r")
> > reader = csv.reader(fin, dialect="excel", quotechar='"', delimiter=",")
> >
> > for line in [reader.next() for i in range(7)]:
> >     p.append(line)
> >
> > fin.close()
> > print p
> > -=-=-=-=-=-=-=-		OUTPUT
> > [['Category', 'Model', 'Caliber', 'Serial #', 'Description',
> > 'Accessories'], ['Air', 'Daisy 717 Pistol', '.177 pellet', '', '', ''],
> > ['Air', 'Daisy/NRA PowerLine 953 Rifle', '.177 pellet', 'n/a',
> > 'Micrometer Peep, "Globe" front (missing alternate inserts', 'Shooting
> > sling'], ['Air', 'RWS Diana Model 54 "Air King" Rifle', '.22 pellet',
> > '4022395', 'Hunting grade - >900fps', '2-7x BSA AOL scope'], ['Air',
> > 'Gamo/NRA', '0.177', '', 'Hunting grade - ~1000fps; NRA markings on
> > barrel, stock', '4x (BSA?) AOL scope, NRA badge'], ['Air',
> > 'Walther/Crossman CP99 Pistol', '.177 pellet', '', 'CO2, repeater
> > (currently magazine jams trigger/safety)', ''], ['Percussion', '? New
> > Orleans Ace boot-pistol', '.36 lead', '', '', '']]
> > -=-=-=-=-=-=-=-		INPUT (just first seven lines)
> > Category,Model,Caliber,Serial #,Description,Accessories
> > Air,Daisy 717 Pistol,.177 pellet,,,
> > Air,Daisy/NRA PowerLine 953 Rifle,.177 pellet,n/a,"Micrometer Peep,
> > ""Globe"" front (missing alternate inserts",Shooting sling
> > Air,"RWS Diana Model 54 ""Air King"" Rifle",.22 pellet,4022395,Hunting
> > grade - >900fps,2-7x BSA AOL scope
> > Air,Gamo/NRA,0.177,,"Hunting grade - ~1000fps; NRA markings on barrel,
> > stock","4x (BSA?) AOL scope, NRA badge"
> > Air,Walther/Crossman CP99 Pistol,.177 pellet,,"CO2, repeater (currently
> > magazine jams trigger/safety)",
> > Percussion,? New Orleans Ace boot-pistol,.36 lead,,,
> >
> >
> >
> > 	But your explanations are unclear... Maybe you wanted the first
> > sublist to be all the first column, etc.
> >
> > -=-=-=-=-=-=-=-		PROGRAM
> > import csv
> >
> > p = None
> >
> > fin = open("firearms.csv", "r")
> > reader = csv.reader(fin, dialect="excel", quotechar='"', delimiter=",")
> >
> > for line in [reader.next() for i in range(7)]:
> >     if not p:
> >         p = [[] for j in range(len(line))]
> >     for c in range(len(line)):
> >         p[c].append(line[c])
> >
> > fin.close()
> > print p
> > -=-=-=-=-=-=-=-		OUTPUT (same input)
> > [['Category', 'Air', 'Air', 'Air', 'Air', 'Air', 'Percussion'],
> > ['Model', 'Daisy 717 Pistol', 'Daisy/NRA PowerLine 953 Rifle', 'RWS
> > Diana Model 54 "Air King" Rifle', 'Gamo/NRA', 'Walther/Crossman CP99
> > Pistol', '? New Orleans Ace boot-pistol'], ['Caliber', '.177 pellet',
> > '.177 pellet', '.22 pellet', '0.177', '.177 pellet', '.36 lead'],
> > ['Serial #', '', 'n/a', '4022395', '', '', ''], ['Description', '',
> > 'Micrometer Peep, "Globe" front (missing alternate inserts', 'Hunting
> > grade - >900fps', 'Hunting grade - ~1000fps; NRA markings on barrel,
> > stock', 'CO2, repeater (currently magazine jams trigger/safety)', ''],
> > ['Accessories', '', 'Shooting sling', '2-7x BSA AOL scope', '4x (BSA?)
> > AOL scope, NRA badge', '', '']]
> > --
> > 	Wulfraed	Dennis Lee Bieber		KD6MOG
> > 	wlfraed at ix.netcom.com		wulfraed at bestiaria.com
> > 		HTTP://wlfraed.home.netcom.com/
> > 	(Bestiaria Support Staff:		web-asst at bestiaria.com)
> > 		HTTP://www.bestiaria.com/
>
> below is the data I am trying to read
>
> "000004"	"AS0042123BO"	"AS 0042.123 ROYAL ELONG SEAT
> BO"	"001610"	"A/S Fixtures"	0	$99.00	3.70	""	"0042123"	11/20/2003
> "000024"	"AS0042001BK"	"AS 0042.001 ROYAL EL*DISC BY
> MFG*BK"	"001610"	"A/S
> Fixtures"	0	$99.00	8.00	"723085611663"	"0042001"	11/20/2003
> "000104"	"CH130TTWH"	"CH 130TT   EL PLAS SEAT C/F W/C
> WH"	"207067"	"Church Seats"	12	$25.00	6.75	"073088079961"	"130TT
> 000"	12/28/1995
[...]

[Fixed top-posting]

You can use a class rather than have lists of lists:

-------------------------------------
print

data = '''
id,category_id,description,price
0024,A1,cup,1.00
0025,A1,saucer,2.00
0026,A1,teapot,5.00'''

class MyClass(object):
    id = None
    category_id = None
    description = None
    price = None

    def __init__(self, id=None, category_id=None, description=None,
price=None):
        self.id = id
        self.category_id = category_id
        self.description = description
        self.price = price

    def __str__(self):
        return '%s - %s' % (self.id,self.description)

myclass_collection = []

import csv

reader = csv.reader( data.splitlines()[1:] )

firstline = reader.next()

for line in reader:
    names_and_values = dict(zip(firstline,line))
    c = MyClass(**names_and_values)
    myclass_collection.append( c )

for item in myclass_collection:
    print item

------------------------

0024 - cup
0025 - saucer
0026 - teapot